
  
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .dynamic-shadow-parent {
          position: relative;
          z-index: 1;
        }
        .dynamic-shadow {
          position: relative;
          width: 10rem;
          height: 10rem;
          background: linear-gradient(75deg, #6d78ff, #00ffb8);
        }
        .dynamic-shadow::after {
          content: '';
          width: 100%;
          height: 100%;
          position: absolute;
          background: inherit;
          top: 0.5rem;
          filter: blur(0.4rem);
          opacity: 0.7;
          z-index: -1;
        }
        </style>
</head>
<body>
    <div class="dynamic-shadow-parent">
    <div class="dynamic-shadow"></div>
  </div>
</body>
</html>